email address probes

From: Andy Bastien <lists+incidents(at)yuggoth.net>
Date: Wed Feb 05 2003 - 15:54:19 EST

Where I work, we've getting lots of attempts to send email to random addresses at our domain. All of these attempts have been coming from valid servers operated by AOL, MSN, and Hotmail. I'm guessing that this is an attempt to find some spam targets, although I suppose that there could be something worse in store.

I'd like to be able to stop these attempts, but I can't think of a way to do it. All of the attempts are coming from valid servers from some domains that we can't block. They do all have null reverse-paths (MAIL FROM:<>), but I don't think that we can reject on this criteria as null reverse-paths are used to send NDRs and other notifications which we don't want to block. I suppose that we could accept the emails and dump them to /dev/null (or to some tarpit account so that we can inspect them) instead of replying with a "550 User unknown," but I suspect that this could cause us more headaches in the future. Does anyone have any suggestions as to how we could handle this problem?

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This list is provided by the SecurityFocus ARIS analyzer service. For more information on this free incident handling, management and tracking system please see: http://aris.securityfocus.com Received on Wed Feb 5 17:02:47 2003